If I could vote, I'd vote Jill Stein & Green. I don't agree with her on everything, but she's my favourite among the lot. That said, the US needs to get a decent voting system and ditch First Past The Post. FPTP as a system of casting votes is no longer fit for purpose, and more of a hindrance in the path of democracy than a vehicle.
You need a system that offers ranking, so you can vote for who you want, not against who you don't, and can stop thinking about voting tactically. It's awful that people have to vote Democrat, simply to stop the Republicans, or risk splitting the vote. If you could say "Jill Stein, but if she fails then Hillary", that would be so much more satisfying.
You need proportional representation (PR), so that everyone is represented according to their proportion, and vote fixing tactics like gerrymandering no longer matter. More importantly, every vote would matter. PR doesn't have to be nationwide, it can offer huge benefits just from amalgamating 4-9 local voting districts.
Also stop thinking in terms of two parties. Have many smaller parties. Have a minority government that has to work together and agree on things to make changes, rather than be able to push things through simply due to a majority (which currently doesn't even represent half the population). Sure, you'd get a few extremists in (who represent the extremists in the country), but they still wouldn't have carte blanche to push through their extremist policies, and maybe then you wouldn't have extremists who thought their voice wasn't getting hurt, and deciding to take a more violent approach to getting their message across.
The Scottish government, is about to start debating whether we should move from AMR to STV. We have a popular minority government, and we're sitting down and discussing how to improve the mechanics of democracy even further. How cool is that?